TRANSMIGRATIONS AND METAMORPHOSES. 



25a 



Echinorhynchus gigas. Pigs disseminate the eggs, and the 

 embryos infest these larvae, in the bodies of which they 

 pass through their principal changes. 



The Gregwrinm are microscopic beings, with an 

 extremely simple organization, the nature and the 

 genealogy of which have only lately been known. They 

 live at first encysted by thousands together, under the 

 name of Psorospermise ; they are afterwards hatched in 

 the form of Amoebse, and then transformed into Gregarinas. 

 They migrate from one animal to another, or from one 

 organ to another, to settle in the intestine, where they 

 assume their adult form. In this state they are mono- 

 cellular, and do not at any time possess organs which 

 resemble the sexual organs of other classes. The disease 

 of silk worms, known by the name of " pebrine," has 

 been attributed to the development of psorospermiae. 



We give the representation (Fig. 74) of gregarinse 

 which we have found abundantly on the Nemertes ; and 



Fig. 74.— Gregarinie of Nemertes 

 Qv&seriensis. 



Fig. 75. 



- Stylorhynchus oligacanthits, from the 

 larva of the Agrion. 



(Fig. 75) a peculiar species which lives in the larva of an 

 agrion. 



